This invention relates to microscope objectives and more particularly to microscope objectives having a numerical aperture of substantially 0.66 and a magnification of 40X, when used with a telescope objective as described in U.S. Pat. No. 3,355,234.
Microscope objectives according to this invention are well corrected for the usual chromatic image aberrations, spherical aberration, coma and astigmatism when used with a telescope objective and have a substantially flat image field.
U.S. Pat. No. 3,437,398 issued Apr. 1969 and describes an objective shown in FIG. 6 which has four components. While the first two elements are singlets, the other two are both doublets and the power, when used with a telescope objective is 20X.
U.S. Pat. No. 3,515,463 issued June 1970 and describes a four-component having doublets as the last two components. The first lens is a concavo-convex singlet, the second and third are biconvex being a singlet and doublet, respectively. The last component is a convex-concavo doublet to provide a power of 45X.
U.S. Pat. No. 3,623,792 issued November 1971 and describes a three-component objective having a magnification of 40X and a numerical aperture of 0.65. All three components are doublets with the second and third components being biconvex.
U.S. Pat. No. 3,902,791 issued September 1975 and describes a four-component microscope objective having a magnification of 40X, when used with a telescope objective, and a numerical aperture of 0.66. All four components are concavo-convex with the third and fourth being doublets. The objective does not have a hemispherical first element and requires an air space of about 8 mm. between the third and fourth components.